Select incorrect reduction process :

Options

A. `2[Ag(CN)_(2)]^(-) + Zn rarr [Zn(CN)_(4)]^(2-) + 2Ag`
B. `2FeO + C overset(Delta)rarr Fe + CO`
C. `8 AI + 3Mn_(3)O_(4) overset(Delta)rarr 4 Al_(2)O_(3) + 9 Mn`
D. `2ZnS + C overset(Delta)rarr 2ZnS + CS_(2)`

Answer

To solve the question of selecting the incorrect reduction process from the given options, we will analyze each option step by step.

### Step 1: Analyze the first option
**Reaction:** Silver cyanide (AgCN) reacts with zinc (Zn) to produce zinc cyanide (Zn(CN)₂) and silver (Ag).

- **Explanation:** Zinc is more reactive than silver, which allows it to displace silver from its compound. This is a displacement reaction where silver is reduced from its +1 oxidation state in AgCN to 0 in metallic Ag.
- **Conclusion:** This reduction process is correct.

### Step 2: Analyze the second option
**Reaction:** Iron oxide (Fe₂O₃) is reduced with carbon (C) to produce iron (Fe) and carbon monoxide (CO).

- **Explanation:** In metallurgy, iron oxide is commonly reduced using carbon, especially in blast furnaces. Carbon acts as a reducing agent, and this reaction is thermodynamically favorable at high temperatures.
- **Conclusion:** This reduction process is correct.

### Step 3: Analyze the third option
**Reaction:** Aluminium (Al) is used in the thermite process to reduce manganese (Mn) or chromium (Cr).

- **Explanation:** Aluminium is highly reactive and can displace less reactive metals like manganese or chromium from their oxides. This process is used in welding and is a valid reduction method.
- **Conclusion:** This reduction process is correct.

### Step 4: Analyze the fourth option
**Reaction:** Zinc sulfide (ZnS) is reduced with carbon (C) to produce carbon sulfide (CS₂).

- **Explanation:** Zinc sulfide must first undergo roasting to convert it into zinc oxide (ZnO) before it can be reduced. Directly reducing ZnS with carbon is incorrect. Additionally, zinc is more reactive than carbon, making this reduction process thermodynamically unfavorable. The Gibbs free energy change (ΔG) for this reaction is positive, indicating that it is non-spontaneous.
- **Conclusion:** This reduction process is incorrect.

### Final Answer
The incorrect reduction process is the fourth option: **Zinc sulfide (ZnS) is reduced with carbon to produce carbon sulfide (CS₂).**

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